Check valves are commonly used in flow lines to permit the flow of fluid in one direction while stopping flow in an opposite direction. A typical prior art check valve permits the fluid to flow directly over a sealing surface located on the check valve. Thus, the sealing surface becomes eroded by the fluid action and expensive procedures; such as, removal of the valve from the flow line and machining the sealing surface to repair the valve or replacing the valve in the flow line, are necessary to insure that the check valve functions properly.
Recently, a check valve was disclosed in copending application Ser. No. 838,148, now U.S. Pat. No. 4,176,680, and including a body having a first portion defining an inlet passage, an outlet passage and a shoulder for directing fluid flow upwardly through an opening into the outlet passageway and having a second portion with a tubular section threadably engaged in the opening for receiving the flowing fluid in one end and then out outlet ports and a flange extending outwardly from the tubular portion at a location below the outlet ports to define an upwardly facing sealing surface. A plunger member was mounted within the body and included a plug slidably mounted within the longitudinal passage and a sleeve mounted to circumscribe the longitudinal section, the sleeve having a shoulder forming a downwardly facing sealing surface which was engagable with the upwardly facing sealing surface on the flange. The sleeve was moved upwardly by the pressure exerted from the fluid on the plug. A spring was mounted with the plunger member to urge the downwardly facing sealing surface into engagement with the upwardly facing sealing surface to thereby prevent fluid communication between the inlet and outlet passageways by stopping fluid flow into the outlet ports when the pressure of the fluid within the inlet passageway is insufficient to overcome the force provided by the spring.
In accordance with the present invention, a check valve is used in a flow line and comprises a valve body including a first portion having an inlet with a passage for carrying fluid from the flow line and an outlet with a passage for carrying the fluid back to the flow line, the inlet and outlet passages being substantially aligned with one another. The valve body further includes a second portion having a tubular member with a longitudinal passage for receiving fluid from the inlet passage and with outlet ports extending radially from the longitudinal passage. A flange extends annularly around the tubular member with a surface spacing the outlet of the first portion. A plunger is mounted with the valve body for preventing fluid flow through the outlet ports of the tubular member and includes a plug mounted with the tubular member in the longitudinal passage for deflecting the flow of fluid out of alignment with the inlet passage and through the outlet ports and further includes a tubular sleeve circumscribing the tubular member with an engaging shoulder facing the flange surface. A spring is mounted with the valve body for urging the plunger toward the inlet passage. The plug thus moves through the longitudinal passage of the tubular member and the shoulder of the tubular member moves toward the flange surface when the pressure of the fluid in the inlet passage is insufficient to overcome the urging of the spring which thereby checks the flow of fluid through the valve.